address comments and create registries

Author: shivaspeaks

xds/src/main/java/io/grpc/xds/internal/matcher/CelStateMatcher.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2026 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.xds.internal.matcher;
+
+import com.github.xds.core.v3.TypedExtensionConfig;
+import dev.cel.common.CelAbstractSyntaxTree;
+import dev.cel.common.CelProtoAbstractSyntaxTree;
+import dev.cel.runtime.CelEvaluationException;
+
+/**
+ * Matcher for CEL expressions handling xDS CEL Matcher extension.
+ */
+final class CelStateMatcher implements Matcher {
+  private final CelMatcher compiledEndpoint;
+
+  CelStateMatcher(CelMatcher compiledEndpoint) {
+    this.compiledEndpoint = compiledEndpoint;
+  }
+
+  @Override
+  public boolean match(Object value) {
+    try {
+      return compiledEndpoint.match(value);
+    } catch (CelEvaluationException e) {
+      return false;
+    }
+  }
+
+  @Override
+  public Class<?> inputType() {
+    return GrpcCelEnvironment.class;
+  }
+
+  static final class Provider implements MatcherProvider {
+    @Override
+    public Matcher getMatcher(TypedExtensionConfig config) {
+      try {
+        com.github.xds.type.matcher.v3.CelMatcher celProto = config.getTypedConfig()
+            .unpack(com.github.xds.type.matcher.v3.CelMatcher.class);
+        if (!celProto.hasExprMatch()) {
+          throw new IllegalArgumentException("CelMatcher must have expr_match");
+        }
+        com.github.xds.type.v3.CelExpression expr = celProto.getExprMatch();
+        if (!expr.hasCelExprChecked()) {
+          throw new IllegalArgumentException("CelMatcher must have cel_expr_checked");
+        }
+        CelAbstractSyntaxTree ast = 
+            CelProtoAbstractSyntaxTree.fromCheckedExpr(
+                expr.getCelExprChecked()).getAst();
+        CelMatcher compiled = CelMatcher.compile(ast);
+        
+        return new CelStateMatcher(compiled);
+      } catch (Exception e) {
+        throw new IllegalArgumentException("Invalid CelMatcher config", e);
+      }
+    }
+
+    @Override
+    public String typeUrl() {
+      return "type.googleapis.com/xds.type.matcher.v3.CelMatcher";
+    }
+  }
+}

xds/src/main/java/io/grpc/xds/internal/matcher/HeaderMatchInput.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2026 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.xds.internal.matcher;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.github.xds.core.v3.TypedExtensionConfig;
+import com.google.protobuf.InvalidProtocolBufferException;
+import io.envoyproxy.envoy.type.matcher.v3.HttpRequestHeaderMatchInput;
+import io.grpc.Metadata;
+import io.grpc.xds.internal.matcher.MatcherRunner.MatchContext;
+
+/**
+ * MatchInput for extracting HTTP headers.
+ */
+final class HeaderMatchInput implements MatchInput {
+  private final String headerName;
+    
+  HeaderMatchInput(String headerName) {
+    this.headerName = checkNotNull(headerName, "headerName");
+    if (headerName.isEmpty() || headerName.length() >= 16384) {
+      throw new IllegalArgumentException(
+          "Header name length must be in range [1, 16384): " + headerName.length());
+    }
+    if (!headerName.equals(headerName.toLowerCase(java.util.Locale.ROOT))) {
+      throw new IllegalArgumentException("Header name must be lowercase: " + headerName);
+    }
+    try {
+      if (headerName.endsWith(Metadata.BINARY_HEADER_SUFFIX)) {
+        Metadata.Key.of(headerName, Metadata.BINARY_BYTE_MARSHALLER);
+      } else {
+        Metadata.Key.of(headerName, Metadata.ASCII_STRING_MARSHALLER);
+      }
+    } catch (IllegalArgumentException e) {
+      throw new IllegalArgumentException("Invalid header name: " + headerName, e);
+    }
+  }
+    
+  @Override
+  public Object apply(MatchContext context) {
+    if ("te".equals(headerName)) {
+      return null;
+    }
+    if (headerName.endsWith(Metadata.BINARY_HEADER_SUFFIX)) {
+      Iterable<byte[]> values = context.getMetadata().getAll(
+          Metadata.Key.of(headerName, Metadata.BINARY_BYTE_MARSHALLER));
+      if (values == null) {
+        return null;
+      }
+      StringBuilder sb = new StringBuilder();
+      boolean first = true;
+      for (byte[] value : values) {
+        if (!first) {
+          sb.append(",");
+        }
+        first = false;
+        sb.append(com.google.common.io.BaseEncoding.base64().encode(value));
+      }
+      return sb.toString();
+    }
+    Metadata metadata = context.getMetadata();
+    Iterable<String> values = metadata.getAll(
+        Metadata.Key.of(headerName, Metadata.ASCII_STRING_MARSHALLER));
+    if (values == null) {
+      return null;
+    }
+    return String.join(",", values);
+  }
+
+  @Override
+  public Class<?> outputType() {
+    return String.class;
+  }
+
+  static final class Provider implements MatchInputProvider {
+    @Override
+    public MatchInput getInput(TypedExtensionConfig config) {
+      try {
+        HttpRequestHeaderMatchInput proto = config.getTypedConfig()
+            .unpack(HttpRequestHeaderMatchInput.class);
+        return new HeaderMatchInput(proto.getHeaderName());
+      } catch (InvalidProtocolBufferException e) {
+        throw new IllegalArgumentException(
+            "Invalid input config: " + config.getTypedConfig().getTypeUrl(), e);
+      }
+    }
+
+    @Override
+    public String typeUrl() {
+      return "type.googleapis.com/envoy.type.matcher.v3.HttpRequestHeaderMatchInput";
+    }
+  }
+}

xds/src/main/java/io/grpc/xds/internal/matcher/HttpAttributesCelMatchInput.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2026 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.xds.internal.matcher;
+
+import com.github.xds.core.v3.TypedExtensionConfig;
+import io.grpc.xds.internal.matcher.MatcherRunner.MatchContext;
+
+/**
+ * MatchInput for extracting CEL environment from HTTP attributes.
+ */
+final class HttpAttributesCelMatchInput implements MatchInput {
+  static final HttpAttributesCelMatchInput INSTANCE = new HttpAttributesCelMatchInput();
+
+  private HttpAttributesCelMatchInput() {}
+
+  @Override
+  public Object apply(MatchContext context) {
+    return new GrpcCelEnvironment(context);
+  }
+
+  @Override
+  public Class<?> outputType() {
+    return GrpcCelEnvironment.class;
+  }
+
+  static final class Provider implements MatchInputProvider {
+    @Override
+    public MatchInput getInput(TypedExtensionConfig config) {
+      return INSTANCE;
+    }
+
+    @Override
+    public String typeUrl() {
+      return "type.googleapis.com/xds.type.matcher.v3.HttpAttributesCelMatchInput";
+    }
+  }
+}

xds/src/main/java/io/grpc/xds/internal/matcher/MatchInput.java

@@ -16,17 +16,25 @@
 
 package io.grpc.xds.internal.matcher;
 
+import io.grpc.xds.internal.matcher.MatcherRunner.MatchContext;
 import javax.annotation.Nullable;
 
 /**
  * Interface for extracting values from a match context (e.g. HTTP headers).
  */
-public interface MatchInput<T> {
+public interface MatchInput {
   /**
    * Extracts the value from the context.
    * @param context the context (e.g. Metadata, Attributes)
    * @return the extracted value, or null if not found.
    */
   @Nullable
-  Object apply(T context);
+  Object apply(MatchContext context);
+
+  /**
+   * Returns the type of value extracted by this input.
+   */
+  default Class<?> outputType() {
+    return Object.class;
+  }
 }

xds/src/main/java/io/grpc/xds/internal/matcher/MatchInputProvider.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2026 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.xds.internal.matcher;
+
+import com.github.xds.core.v3.TypedExtensionConfig;
+
+/**
+ * Provider interface for creating {@link MatchInput} instances.
+ */
+public interface MatchInputProvider {
+  /**
+   * Returns the corresponding {@link MatchInput} for the given config.
+   */
+  MatchInput getInput(TypedExtensionConfig config);
+
+  /**
+   * Returns the type URL supported by this provider.
+   */
+  String typeUrl();
+}

xds/src/main/java/io/grpc/xds/internal/matcher/MatchInputRegistry.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2026 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.xds.internal.matcher;
+
+import com.google.common.annotations.VisibleForTesting;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import javax.annotation.Nullable;
+
+/**
+ * Registry for {@link MatchInputProvider}s.
+ */
+public final class MatchInputRegistry {
+  private static final MatchInputRegistry DEFAULT_INSTANCE = new MatchInputRegistry();
+
+  private final Map<String, MatchInputProvider> providers = new ConcurrentHashMap<>();
+
+  public static MatchInputRegistry getDefaultRegistry() {
+    return DEFAULT_INSTANCE;
+  }
+
+  @VisibleForTesting
+  public MatchInputRegistry() {
+    register(new HeaderMatchInput.Provider());
+    register(new HttpAttributesCelMatchInput.Provider());
+  }
+
+  public void register(MatchInputProvider provider) {
+    providers.put(provider.typeUrl(), provider);
+  }
+
+  @Nullable
+  public MatchInputProvider getProvider(String typeUrl) {
+    return providers.get(typeUrl);
+  }
+}

xds/src/main/java/io/grpc/xds/internal/matcher/Matcher.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2026 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.xds.internal.matcher;
+
+/**
+ * Interface that defines a matcher that can match a given value.
+ */
+public interface Matcher {
+  /**
+   * Returns true if the value matches the matcher.
+   */
+  boolean match(Object value);
+
+  /**
+   * Returns the type of value accepted by this matcher.
+   */
+  default Class<?> inputType() {
+    return Object.class;
+  }
+}